Vagina too loose? Am I too wet during intercourse?

My boyfriend and I just started having intercourse. After we get the condom on him ( his girth is very wide and he is pretty long in length when he is hard) and we just discovered that he actually needs an extra large condom because we have difficulty getting even a large condom on him without some struggle (it doesnt go on very easily). But we have been using large condoms to finish the box off. When we are in the cowgirl position he stays very hard and i can feel him inside me and it feels great. But when i get tired and we change positions to missionary it seems as if he doesnt get 100% soft but he gets a great deal softer then he was when we started and its hard to get him to stay inside me and i cant feel anything...on days when we can get it to stay inside of me its still not as hard as during missionary or during oral sex and I still cant feel very much and I dont think he can either. The only way I feel anything is if he pounds away at me like a jackhammer. And at the beginning of sex, after foreplay, when he first sticks it in its tight and i definitley feel him going inside and i know he does too...and sometimes it even hurts a little....but after awhile when his penis is wet i just feel nothing. Im not sure if he doesnt...I know i should ask. Is it me? or may he be having a little shyness performing and pleasing me and its makes him soft? I dont know but I really love this guy and I just want to please him and to make it work between us in bed? Does anyone have any suggestions or answers as to why this is happening? Also even though he says it doesnt hurt him i think the large condoms are too small and that it may be taking away from his pleasure during sex. But during missionary everything is great!! Im confused...please help!! Also Im a little scared that my vagina may be too loose! but if that is the case why do i feel so tight when he first starts out? when i get aroused do i get too aroused and wet?? help!!